Austria-Hungary

Austria-Hungary was a constitutional union of the Austrian Empire and the Kingdom of Hungary from 1 March 1867 to 31 October 1918, with its capital at Vienna. The union was created in the aftermath of the failed Austro-Prussian War of 1866, and it was a multinational state, with 239,977 square miles of territory. Austria-Hungary ruled over much of Central Europe, Eastern Europe, and South Europe, controlling the present-day Czech Republic, Slovakia, Bosnia and Herzegovina, Montenegro, Croatia, and Slovenia and parts of Italy, Ukraine, and Poland in addition to Austria and Hungary. Austria-Hungary was an ally of the German Empire and the Ottoman Empire, and it dissolved after the defeat of the Central Powers in 1918 in World War I.

History
In the aftermath of the 1848 Hungarian Revolution and the Austro-Prussian War of 1866, the Austrian Empire and the Kingdom of Hungary (both ruled in a personal union by the Emperor of Austria) were weakened. On 1 March 1867, the Austrian Empire and the Kingdom of Hungary (led in union by Emperor Franz Joseph I of Austria) signed the 1867 Compromise, which established a real union between the two countries. The armed forces were united under the Emperor-King and foreign affairs, defense, and finance were decided by him, while Austria and Hungary had separate prime ministers and parliaments.

Austria-Hungary consisted of several present-day countries, ruling over much of central Europe and eastern Europe, owning the region of Czechoslovakia, southern Poland, and Galicia (the western half of Ukraine) to the north, while to the south they owned much of the Balkans (including Bosnia and Herzegovina, Montenegro, Croatia, and Slovenia) in addition to Transylvania (the mountainous region of western Romania and eastern Hungary).

The dual monarchy of Austria-Hungary, a Great Power along with the Russian Empire, German Empire, United Kingdom, France, and the United States, was one of the strongest countries on the planet. They allied with Germany in the Austro-German Alliance of 1878-1918, joined the German and Russian empires in the Three Emperors' Alliance in 1881-1887, an alliance with the Kingdom of Serbia in the 1881-95 Austro-Serbian Alliance, the Kingdom of Italy and Germany in the 1882-1915 Triple Alliance, and the Austro-German-Romanian Alliance of 1883-1916. They consolidated their positions in Europe with these alliances, although some were very brief. The Three Emperos' Alliance ended in 1887 because of Austria-Hungary and Russia's conflicting interests in the Balkans, and the alliance with Serbia ended for similar reasons in 1895. Austria-Hungary expanded its non-European empire by annexing Tianjin in China as a colonial concession in 1901 following the Boxer Rebellion, during which it sent marines to guard its embassy to the Qing Dynasty. It also sent the Austro-Hungarian Navy and some troops to assist in the fquelling of the xenophobic Boxers and the Qing Army.

Austria-Hungary became a threat to the Balkans starting in 1878, when it occupied Bosnia and Herzegovina after some resistance from Bosniak Muslims - Austria-Hungary was given the right to occupy the region by the Congress of Berlin, which followed the Third Russo-Turkish War.